The present palimpsest was originally written in 11th c. in the rare Palaeo–Frankish, or St. Amand, music notation on a single red staff. In the 14th c. the text and single red staff was kept, while the rest of the music was partly erased and rearranged with the same music, but in a partly polyphonic setting of the mass in square music notation with 4 red lines added. Unusual in showing the change in music notation as well as an early attempt at polyphonic setting. 1 p. was erased but with no new music added.